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nc                     NOTOGAEA,   NEOGAEA,   AND   ARCTOGAEA                   &5
the realm of Notogaea), and Madagascar; and finally, the realm
of Antarctogaea or Atheriogaea, which embraces JSTew Zealand,
the Antarctic continent., and a series of islands such as South
G-eorgia and Kerguelen, and possibly even the extreme south of
Patagonia. This latter quarter of the globe will need no further
reference, as it has no truly indigenous terrestrial mammalian
inhabitants. We cannot include the Bats in this statement, as
their distribution is due to different powers of extending their
range, and to different barriers from those which govern the
range of other groups of mammals.
(1)  I^otogaea.1     This realm is characterised by the exclusive
possession of the  Monotremes:—that is to say, one of the two
primary divisions   of the   Mammalia  is   ahsolutely restricted to
this   area.       It   contains,   moreover,   the   vast   majority   of   the
Marsupials.      Further,  the   realm   of   ISTotogaea  is   to   be   dis-
tinguished  by the  entire absence  of the  higher mammals, with
the exception of a  few small Rodents.     (The Bats  are ignored
for the reasons stated, and the Dingo is believed to have been an
importation.)   It cannot be disputed that this is a very distinctly-
marked area of the earth's surface.
(2)  JSTeogaea.       The   continent   of   South   America   has   no
Monotremes and  only a few  Marsupials, all  of which, with the
exception of Caenolestes, belong to the  Polyprotodont division of
that order, and to a peculiar family, Didelphyidae.     The  recent
discovery  of  other  fossil  Marsupials, however,  to   some   extent
favours   Huxley's  view  that   3STeogaea   and   ISTotogaea  form   one
realm   as   opposed   to   the   rest   of   the   world.      Besides   this,
IsTeogaea possesses the Edentata, which are found nowhere else ;----
that   is,   the   division   of  the  Edentata  to  which   the   name   is
now restricted by some  authorities.      It is also characterised by
the nearly entire absence of  the important order of Insectivora;
and, as minor marks of distinction, by the  absence of Antelopes,
Oxen and Sheep, of the Ichneumon tribe, of Horses, and of Lemurs.
It  has  the  exclusive  possession of the  Hapalidae and  Cebidae,
and of several families of Rodents.
(3)  Arctogaea.      This vast  realm is  clearly  capable  of sub-
division into  four  regions,  which will  be  considered  in   detail
later.     In the meantime the points of likeness between these sub-
divisions is more marked than are either the resemblances or the
1 This term, ia sometimes used in a wider sense ; cf. voL viii. p. 74.